Eli Lilly and Company / CrossBridge Bio, Inc.

TROP2-expressing solid tumors (breast, NSCLC, urothelial, gynecologic)

600K US cases/yr · $4.0B Global TROP2 ADC market (2025, Trodelvy + Datroway combined sales trajectory) · $1,300 Trodelvy 2024 global sales (USD millions)

Disease Overview

TROP2 (trophoblast cell-surface antigen 2) is a transmembrane glycoprotein overexpressed on the majority of epithelial solid tumors, making it one of the most heavily validated ADC targets in oncology. Major TROP2-expressing indications include triple-negative breast cancer (TNBC, ~15,000 US new cases/year), HR+/HER2- metastatic breast cancer (majority of the ~290,000 US breast cancer incidence annually), non-small cell lung cancer (~230,000 US new cases annually, with ~30% TROP2-high), and urothelial carcinoma (~83,000 US new cases). Two TROP2 ADCs are FDA-approved: Gilead's Trodelvy (sacituzumab govitecan, TOP1i payload SN-38) approved in TNBC (2020), HR+ breast (2023), and urothelial (accelerated 2021, voluntarily withdrawn 2024); and AstraZeneca/Daiichi Sankyo's Datroway (datopotamab deruxtecan, TOP1i payload DXd) approved in HR+/HER2- breast (Jan 2025) and NSCLC (June 2025). Trodelvy generated ~$1.3B in 2024 sales; Datroway analyst consensus is $2-3B peak. Next-gen TROP2 ADCs seek to improve therapeutic index via site-specific conjugation, novel payloads, and combination biology. CrossBridge's CBB-120 combines topoisomerase-1 inhibitor (TOP1i) and ATR inhibitor (ATRi) as dual payloads, exploiting DNA-damage-response synthetic lethality. Primary source: Gilead/Trodelvy and AstraZeneca/Datroway FDA approval materials.

Competitive Landscape

The TROP2 ADC landscape has evolved from open race to entrenched duopoly with next-generation challengers. (1) Approved TROP2 ADCs — Trodelvy (sacituzumab govitecan, Gilead) was the first-in-class TROP2 ADC with cleavable CL2A linker and SN-38 (TOP1i) payload; Datroway (datopotamab deruxtecan, AZ/Daiichi) uses GGFG tetrapeptide linker with DXd (TOP1i) payload and has shown superior tolerability in multiple indications. (2) Next-generation TOP1i mono-payload challengers — Merck/Kelun's sacituzumab tirumotecan (sac-TMT, MK-2870) showed Phase 3 wins in EGFR-mutant NSCLC (2024) and is advancing broadly; Innovent's IBI343 and Hengrui's SHR-A1921 are China-based Phase 2/3 TROP2 ADCs. (3) Dual-payload next-gen — CrossBridge's CBB-120 (TOP1i + ATRi, now Lilly's) is the lead dual-payload challenger, with preclinical data showing superiority to Dato-DXd in xenograft models; Sutro Biopharma's STRO-004 (preclinical) is another dual-payload candidate. (4) Non-TOP1i payloads — Pfizer/Seagen's PF-08046032 (microtubule payload) and earlier-generation anti-TROP2 with MMAE have been largely displaced. Lilly's CrossBridge bet positions dual-payload as the Gen-3 TROP2 frontier.